检索结果-南通市图书馆

An asymmetrical multilevel inverter with minimum voltage stress and fewer components for photovoltaic renewable-energy system

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Clean Energy 2024年第1期8卷 1-22页

作者： Rabail Memon Mukhtiar ahmed mahar Abdul Sattar Larik Syed Asif Ali shah Department of Electrical Engineering Mehran University of Engineering and TechnologyJamshoroPakistan

The enhanced power quality provided by multilevel inverters(MLIs)has made them more appropriate for medium-and high-power applications,including photovoltaic ***,a prevalent limitation involves the necessity for numerous switches and increased voltage stress across these switches,consequently increasing the overall system *** address these challenges,a new 17-level asymmetrical MLI with fewer components and low voltage stress is proposed for the photovoltaic *** innovative MLI configuration has four direct current(DC)sources and 10 *** on the trinary sequence,the proposed topology uses photovoltaics with boost converters and fuzzy logic controllers as its DC *** equations are used to calculate cru-cial parameters for this proposed design,including total standing voltage per unit(TSVPU),cost function per level(CF/L),component count per level(CC/L)and voltage stress across the *** comparison is conducted by considering switches,DC sources,TSVPU,CF/L,gate driver circuits and CC/L with other existing MLI *** analysis is carried out under various conditions,encompassing different levels of irradiance,variable loads and modulation *** reduce the total harmonic distortion of the suggested topology,the phase opposition disposition approach has been *** suggested framework is simulated in MATLAB®/Simulink®.The results indicate that the proposed topology achieves a well-distributed stress profile across the switches and has CC/L of 1.23,TSVPU of 5 and CF/L of 4.58 and 5.76 with weight coefficients of 0.5 and 1.5,*** values are not-ably superior to those of existing MLI *** results demonstrate that the proposed topology maintains a consistent output at varying irradiance levels with FLCs and exhibits robust performance under variable loads and diverse modulation ***,the total harmonic distortion achieved with phase opposition disposi

关键词： asymmetrical multilevel inverter photovoltaic system renewable energy component count per level cost function per level total standing voltage per unit phase opposition disposition technique

The surveillance of arsenic levels in the drinking water of primary schools and the assessment of the potential cancer-related health risks of children in Multan, Pakistan

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Emerging Contaminants 2024年第1期10卷 17-23页

作者： Hidayatullah mahar Abdul Rehman Memon Aqsa Ishfaq Suhail ahmed Soomro Mehran University of Engineering&Technology JamshoroPakistan NFC Institute of Engineering&Technology MultanPakistan

To investigate the levels of arsenic(As)in the groundwater and drinking water of primary schools and their potential impact on human health is main objective of this *** assess risk,the following parameters i.e.,carcinogenic indices(CI),hazardous indexes(HI),carcinogenic risk(CR),and hazardous quotient(HQ)have been measured for both dermal and oral arsenic *** study has been focused on primary schools located in four tehsils of Multan,where water samples were *** levels,with concentrations ranging from 3.31 to 191 mg/l,exceeding the safe limit set by the World Health Organization(WHO)have been detected in 99.9%of the *** results show that arsenic content ranged from 3.31 to 191 mg/l,with 99.9%of the samples exceeding the World Health Organization's safe limit of 10 mg/*** CR and CI exceeded the USEPA limit of 10–6 in all four tehsils ranged from 2.6×10^(-6) to 9.4×10^(-6) and 0.00023 to 0.0009 respectively in both dermal and oral cases.,Multan Sadar(1.51,1.39)and Multan City(1.76,1.71)exhibited HI and HQ values that surpassed the threshold of 1.0,signaling a significant likelihood of chronic and cancer-causing health consequences for individuals who are exposed to polluted water causing *** findings suggest that the groundwater in the Multan district poses a significant health risk to humans due to high levels of arsenic *** contamination is associated with an increased risk of mortality from internal cancers(including liver,kidney,lung,and bladder),as well as a higher HI&CI incidence of skin ***,pregnancy outcomes are affected,with associations found between arsenic exposure and lower birth weight,and infant *** researchers propose that water supply organizations and educational institutions promptly take measures to ensure that the affected areas have access to arsenic-free drinking water for the well-being of students and residents.

关键词： Risk assessment Drinking water contamination Arsenic Primary school Pakistan

Inducing opto-electronic and spintronic trends in bilayer h-BN through TMO3 clusters incorporation: Ab-initio study

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Physics B 2019年第11期28卷 284-294页

作者： Irfan ahmed Muhammad Rafique Mukhtiar ahmed mahar Abdul Sattar Larik Mohsin Ali Tunio Yong Shuai Mehran University of Engineering and Technology SZABCampusKhairpur Mirs’Pakistan School of Energy Science and Engineering Harbin Institute of TechnologyHarbin 150001China Mehran University of Engineering and Technology JamshoroSindhPakistan

The band structure, magnetism, charge distribution, and optics parameters of TMO3–h-BN hybrid systems are investigated by adopting first-principles study(FPS) calculations. It is observed that the TMO3 clusters add finite magnetic moments to bilayer h-BN(BL/h-BN), thereby making it a magnetic two-dimensional(2D) material. Spin-polarized band structures for various TMO3–BL/h-BN hybrid models are calculated. After the incorporation of TMO3, BL/h-BN is converted into semimetal or conducting material in spin up/down bands, depending on the type of impurity cluster present in BL/h-BN lattice. Optics parameters are also investigated for the TMO3–BL/h-BN complex systems. The incorporation of TMO3 clusters modifies the absorption and extinction coefficient in visible range, while static reflectivity and refraction parameter increase. It can be surmised that the TMO3 substitution in BL/h-BN is a suitable technique to modify its physical parameters thus making it functional for nano/opto-electronic applications, and an experimental approach can be adapted to reinforce the outcomes of this study.

关键词： bilayer h-BN band structure density of states magnetic moments optics

Performance Evaluation of Energy Meters Under Nonlinear Loads

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Journal of Shanghai Jiaotong university(Science) 2017年第2期22卷 133-138页

作者： GUL Mehr 邰能灵 mahar Mukhtiar ahmed 黄文焘 LARIK Abdul Sattar Department of Electrical Engineering Shanghai Jiao Tong University Department of Electrical Engineering Balochistan University of Information Technology Engineering and Management Sciences (BUITEMS) Department of Electrical Engineering Mehran University of Engineering & Technology

Due to rapid advancements in power electronics, the utilization of electronically switched loads and nonlinear loads is increasing gradually in the electrical power system. These loads create problems of measuring instruments, when connected to the power distribution systems. In this paper, an experimental investigation has been carried out to analyze the performance of single-phase watt-hour (induction and electronic types) energy meters that are being used in Pakistan. The accuracy of the energy meters has been tested under different household nonlinear loads, at various power factors and also at different supply voltage levels. Power factor and total harmonic distortion (THD) of different household loads are also recorded in the experimental work. A hardware based experimental setup has been designed to perform the experimental work. The experimental results have been compared to Water and Power Development Authority (WAPDA) standards for energy meters. © 2017, Shanghai Jiaotong University and Springer-Verlag Berlin Heidelberg.

关键词： energy meter accuracy nonlinear loads experimental investigation harmonic distortion power factor

Power Factor Improvement of AC-DC Converter Based on Separately Excited DC Motor Using Passive Filter

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Open Journal of Energy Efficiency 2016年第3期5卷 71-77页

作者： Shazia Baloch Mukhtiar ahmed mahar Raza Haider Shakeel ahmed Electrical Engineering Department Balochistan University of Engineering and Technology Khuzdar Pakistan Electrical Engineering Department Mehran University of Engineering and Technology Jamshoror Pakistan Civil Engineering Department Balochistan University of Engineering and Technology Khuzdar Pakistan

In industries DC motor drives are very essential due to their high performance applications such as its reliability, ease of control, low cost and simplicity. And speed control of these motors is very easy due to power electronic AC-DC converters. These power electronic converters are with prominent low power factor and higher Total Harmonic Distortion (THD). These converters operate only for short time resulting non-sinusoidal waveform. This problem of harmonic distortion can be mitigated by reshaping the non-sinusoidal waveform to pure sine wave. Different wave shaping techniques have been developed by using different filters among which one is tuned passive filter. This paper proposed power factor improvement and harmonic mitigation of AC-DC converters based on separately excited DC motor using tuned passive filter. In this context experimental model is designed and results are analyzed by power quality analyzer.

关键词： DC Motors AC-DC Converters Power Factor Total Harmonic Distortion Passive Filters

Temporal change assessment of agricultural land by Satellite Remote Sensing (SRS) technique

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Natural Science 2013年第6期5卷 689-694页

作者： Gohar Ali mahar Razzaq ahmed Mohammad Jawed Iqbal Ain Zubaida Unit for Rehabilitation and Groundwater Research King Abdulaziz University Jeddah KSA Department of Geography Federal Urdu University of Art Sciences and Technology Karachi Pakistan

Agriculture is the vital economic activity of rural society in nearly all of Pakistan. The Winder-Sonmiani area located at the Makran coast near the city of Hub in Pakistan is economically very promising. Cropping, horticulture, fruit farming and animal husbandry are the common land use activities in the area while fishing along the coast is an important economic activity. Owing to the use of the Satellite Remote Sensing technique (SRST), the triangular basin shape structure of the Winder area has been found to be spatially very promising for agricultural activities. Positive change in the use of agriculture land was detected from the Satellite images of different periods. Use of modern technology and incentives provided by the government have advanced improvement in agriculture.

关键词： Agriculture Spatiotemporal Satellite Remote Sensing (SRS) GIS Landsat

Optimizing Yield and Quality of Canola Cultivars Using Various Potash Levels

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

American Journal of Plant Sciences 2015年第8期6卷 1233-1242页

作者： Ansaar ahmed Fayaz Ali Inamullah Amjad Ali Arif Ullah Rubina Naz Amanullah mahar Shahmir Ali Kalhoro Department of Agronomy The University of Agriculture Peshawar Pakistan College of Natural Resources and Environment Northwest A&F University Yangling China College of Economics and Management Northwest A&F University Yangling China Department of Botany Kohat University of Science & Technology Kohat Pakistan Centre for Environmental Sciences University of Sindh Jamshoro Pakistan Faculty of Agriculture Lasbela University of Agriculture Water & Marine Sciences Lasbela Pakistan

The response of several canola cultivars to different potassium (K) levels was investigated in terms of various agronomic parameters including yields, oil and protein contents in a trial conducted at The University of Agriculture, Peshawar-Pakistan in Rabi 2010-11. Three cultivars including Bulbul-98, Abaseen-95 and Dure-NIFA, with five levels of potassium i.e. 0, 30, 60, 90 and 120 kg·ha-1 were used in Randomized Complete Block (RCB) design with four replications and factorial arrangement. A larger number of days to 50% flowering (116.6 days), plant height (203.8 cm), leaf area index (4.4), 1000 grain weight (3.5 g), biological yield (13189.3 kg·ha-1), grain yield (1799.2 kg·ha-1) and harvest index (13.9%) were obtained in K applied plots than the plots where K was not applied. The highest oil (45.1%) and protein (27.7%) was obtained in plots where K was applied at the rate of 120 and 90 kg·ha-1, respectively. Among cultivars, Bulbul-98 and Abaseen-95 had higher seed yield and oil percentage. Bulbul-98 had more protein content than Abaseen-95 and Durre-NIFA. On average, cultivars gave higher and at par grain yield at 60, 90 and 120 kg·ha-1. However, they produced higher and at par oil and protein percentage at 90 and 120 kg·ha-1. Bul-bul-98 and Abaseen-95 are recommended for higher grain yield and oil content for general culti-vation in Peshawar valley. However, for higher protein content, Bulbul-98 is better. Potassium applied at 60 kg·ha-1 is recommended for higher grain yield, however, for higher oil and protein content, K at 90 kg·ha-1 is recommended.

关键词： Biological Yield Canola Potassium Harvest Index Protein Oil

Okra Leaves—Agricultural Waste for the Removal of Cr(III) and Cr(VI) from Contaminated Water

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

American Journal of Analytical Chemistry 2016年第4期7卷 395-409页

作者： Mazhar Iqbal Khaskheli Saima Qayyum Memon Zaheer ahmed Chandio Wahid Bux Jatoi Mohammad Tariq mahar Faiz Mohammad Khokhar M. A. Kazi Institute of Chemistry University of Sindh Jamshoro Pakistan Institute of Chemistry Shah Abdul Latif University Khairpur Sindh Pakistan

The present study demonstrates the sorptive efficiency of okra leaves for the Cr(III) and Cr(VI) in aqueous system. The batch dynamic sorption method was carried out as the function of the pH of the solution, sorbent doze, initial bulk concentration, shaking speed and contact time. The experimental data were examined by Langmuir and Freundlich isotherms. Cr(III) at pH-4.0 and Cr(VI) pH-2.0 showed a maximum sorption capacities 221.17 mg/g and 81.94 mg/g respectively. Kinetically experimental data of both chromium species were well fitted to pseudo second order rate, Elovich, Morris-Weber and Richenberg equations. Positive values of enthalpy change and negative values of Gibbs free energy indicated the endothermic and spontaneous nature of sorption reaction respectively. The developed method was applied to real ground water samples (affected by industrial wastewater). Up to 92.15% of chromium metal was removed from the real water samples.

关键词： Okra Leaves Chromium Pseudo Second Order

Effect of Boron Soil Application on Nutrients Efficiency in Tobacco Leaf

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

American Journal of Plant Sciences 2015年第9期6卷 1391-1400页

作者： Fayaz Ali Amjad Ali Hameed Gul Muhammad Sharif Arooj Sadiq Ansaar ahmed Arif Ullah Amanullah mahar Shahmir Ali Kalhoro College of Natural Resources and Environment Northwest A & F University Yangling China Pakistan Tobacco Board Tobacco Research Station Mardan Pakistan Department of Soil and Environmental Sciences University of Agriculture Peshawar Pakistan Department of Agriculture Resource and Environmental Sciences Northeast Agriculture University Harbin China Department of Agronomy University of Agriculture Peshawar Pakistan College of Economics and Management Northwest A & F University Yangling China Faculty of Agriculture Lasbela University of Agriculture Water & Marine Sciences Lasbela Pakistan

The present study was based on the general hypothesis that boron may affect the accumulation and utilization of other nutrients in plant. For this purpose a field experiment was carried out to find out the influence of boron on the different nutrients content in FCV tobacco (Nicotiana tabacum L.) at TRS Khan Garhi, Mardan, during 2010-2011. Two varieties TM-2008 and Speight G-28 were tested and six levels of boron (0, 0.5, 1, 2, 3 and 5 kg·ha-1) were applied in the form of boric acid, in randomized complete block design in split plot arrangement and replicated thrice. Results indicated that the yield of tobacco crop increased with 1 kg·B·ha-1 and then decreased sequence wise in both varieties. N and P concentrations were significantly affected by applied boron. Similarly, potassium was increased which is a good indication for a better quality of tobacco crop. Application of boron significantly increased the concentrations of boron nutrients ratios such as K/B;Cl/B and Mn/Fe were decreased while K/Cl and Zn/Cu ratios were increased at lower boron concentrations but decreased at higher concentrations of boron. The fertilizer use efficiency of both the cultivars showed similar trend;however, Speight G-28 was more efficient than TM-2008 in boron accumulation. The overall results revealed that the application of boron should be encouraged for balancing nutrients concentration, thus getting higher yield in the prevailing conditions.

关键词： Boron Nutrients Efficiency Nitrogen Phosphurus Tobacco